zuul各版本實現存在一些微小的變化，總的實現思想未改變，以spring-cloud-netflix-core-1.3.6.RELEASE為例
一、zuul的重要的初始化類
org.springframework.cloud.netflix.zuul.ZuulServerAutoConfiguration
org.springframework.cloud.netflix.zuul.ZuulProxyAutoConfiguration
org.springframework.cloud.netflix.zuul.ZuulFilterInitializer
org.springframework.cloud.netflix.zuul.RibbonCommandFactoryConfiguration
ZuulServerAutoConfiguration
初始化路由規則
初始化一些重要的filter如PreDecorationFilter，RibbonRoutingFilter
初始化ZuulFilterInitializer
初始化ZuulHandlerMapping
代碼如下
//路由規則@Bean @ConditionalOnMissingBean(DiscoveryClientRouteLocator.class) public DiscoveryClientRouteLocator discoveryRouteLocator() { return new DiscoveryClientRouteLocator(this.server.getServletPrefix(), this.discovery, this.zuulProperties, this.serviceRouteMapper); } // pre filters @Bean public PreDecorationFilter preDecorationFilter(RouteLocator routeLocator, ProxyRequestHelper proxyRequestHelper) { return new PreDecorationFilter(routeLocator, this.server.getServletPrefix(), this.zuulProperties, proxyRequestHelper); } // route filters @Bean public RibbonRoutingFilter ribbonRoutingFilter(ProxyRequestHelper helper, RibbonCommandFactory<?> ribbonCommandFactory) { RibbonRoutingFilter filter = new RibbonRoutingFilter(helper, ribbonCommandFactory, this.requestCustomizers); return filter; } @Configuration protected static class ZuulFilterConfiguration { @Autowired private Map<String, ZuulFilter> filters; @Bean public ZuulFilterInitializer zuulFilterInitializer( CounterFactory counterFactory, TracerFactory tracerFactory) { FilterLoader filterLoader = FilterLoader.getInstance(); FilterRegistry filterRegistry = FilterRegistry.instance(); return new ZuulFilterInitializer(this.filters, counterFactory, tracerFactory, filterLoader, filterRegistry); } } @Bean public ZuulController zuulController() { return new ZuulController(); } @Bean public ZuulHandlerMapping zuulHandlerMapping(RouteLocator routes) { ZuulHandlerMapping mapping = new ZuulHandlerMapping(routes, zuulController()); mapping.setErrorController(this.errorController); return mapping; }ZuulProxyAutoConfiguration
zuulProxAutoConfiguration繼承ZuulServerAutoConfiguration功能上和zuulServerAutoConfiguration
主要功能是增加了RibbonCommandFactoryConfiguration的配置，初始化所有的實現ribbon的方式如apache,okhttp。
ZuulFilterInitializer
該類的作用主要是把初始化的過濾器註冊到zuul的FilterRegistry，FilterRegistry是一個單例用於初始化路由信息，在ZuulRunner中使用
RibbonCommandFactoryConfiguration
主要作用是配置轉發的實現，實現主要有apache，okhttp
二、zuul的轉發實現
首先第一步轉到ZuulHandlerMapping中的lookupHandler方法，把轉發轉到zuulController中
@Override protected Object lookupHandler(String urlPath, HttpServletRequest request) throws Exception { if (this.errorController != null && urlPath.equals(this.errorController.getErrorPath())) { return null; } String[] ignored = this.routeLocator.getIgnoredPaths().toArray(new String[0]); if (PatternMatchUtils.simpleMatch(ignored, urlPath)) { return null; } RequestContext ctx = RequestContext.getCurrentContext(); if (ctx.containsKey("forward.to")) { return null; } if (this.dirty) { synchronized (this) { if (this.dirty) { registerHandlers(); this.dirty = false; } } } return super.lookupHandler(urlPath, request); }第一次訪問時dirty為true會初始化一次請求規則如下
private void registerHandlers() { Collection<Route> routes = this.routeLocator.getRoutes(); if (routes.isEmpty()) { this.logger.warn("No routes found from RouteLocator"); } else { for (Route route : routes) { registerHandler(route.getFullPath(), this.zuul); } } }第二步ZuulController繼承ServletWrappingController的會把請求轉到ZuulServlet中如下
/** * @author Spencer Gibb */public class ZuulController extends ServletWrappingController { public ZuulController() { setServletClass(ZuulServlet.class); setServletName("zuul"); setSupportedMethods((String[]) null); // Allow all } @Override public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response) throws Exception { try { // We don't care about the other features of the base class, just want to // handle the request return super.handleRequestInternal(request, response); } finally { // @see com.netflix.zuul.context.ContextLifecycleFilter.doFilter RequestContext.getCurrentContext().unset(); } }}第三步ZuulServlet的service方法如下主要執行pre,route,postRoute三種路由器
@Override public void service(javax.servlet.ServletRequest servletRequest, javax.servlet.ServletResponse servletResponse) throws ServletException, IOException { try { init((HttpServletRequest) servletRequest, (HttpServletResponse) servletResponse); // Marks this request as having passed through the "Zuul engine", as opposed to servlets // explicitly bound in web.xml, for which requests will not have the same data attached RequestContext context = RequestContext.getCurrentContext(); context.setZuulEngineRan(); try { preRoute(); } catch (ZuulException e) { error(e); postRoute(); return; } try { route(); } catch (ZuulException e) { error(e); postRoute(); return; } try { postRoute(); } catch (ZuulException e) { error(e); return; } } catch (Throwable e) { error(new ZuulException(e, 500, "UNHANDLED_EXCEPTION_" + e.getClass().getName())); } finally { RequestContext.getCurrentContext().unset(); } }四、最後由SendResponseFilter執行返回結果,filterOrder為1000所以最好post的filter不要超過1000否則影響返回結果
以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持武林網。